Move scoped_model_counter to provider_counter (#82)

I used `flutter create` anew, so the project structure now has additional 2 `AndroidManifest.xml` files. Everything else stayed the same, so from git’s perspective, it’s just moved files.

provider_counter/README.md

@@ -0,0 +1,25 @@
+# Provider Counter
+
+The starter Flutter application, but using Provider to manage state.
+
+This app is a direct counterpart to the
+[simple counter application](https://flutter.io/docs/development/ui/widgets-intro#changing-widgets-in-response-to-input)
+that you get when you create a new Flutter project. That one uses a `StatefulWidget` to manage
+application state. The version in this repository uses a simple app state management approach,
+`Provider`.
+
+It shows how you might deal with state that is modified from outside the app (for example,
+state synchronized over network) and which needs to be accessed and changed
+from different parts of your app.
+
+## Getting Started
+
+The only important part of the app is the `lib/main.dart` file. It has comments that will walk you
+through it.
+
+For more information on the `provider` package (where `Provider` comes from), please
+[see the package documentation](https://pub.dartlang.org/packages/provider).
+
+For more information on state management in Flutter, and a list of other approaches,
+head over to the
+[State management page at flutter.dev](https://flutter.dev/docs/development/data-and-backend/state-mgmt).